I have a Sony Cybershot DSC-W150 and also a W7. I have trouble taking photos indoors and I am going to Italy and will be in a lot of cathedrals. Is there an inexpensive external flash that can work with one or both of these? Sony makes something for closeup photography, but that's all. I was hoping to pick up something on e-bay, but I have to know what I'm looking for. Thanks.

Your best bet would probably be to buy one of the Digital Aware Slave flash models. These are designed to ignore a digital camera's metering preflash, firing with the camera's main flash instead. If you try to use a slave flash that's not "digital aware", you'll end up with a photo that is illuminated by the camera's flash only (since the slave will fire on the preflash and won't contribute anything to the actual exposure).

Here's one example of a slave flash that's designed to work with digital cameras.

But, it's a relatively weak flash for a larger area (especially if you zoom in much), with GN (Guide Number) of 92 feet at ISO 100.

Your cameras are going to be down to a widest available aperture of around f/5.6 if you zoom in much. To determine flash range, you need to divide the GN by the aperture you're using.

For example, with that flash, using an aperture of f/5.6, with the camera set to ISO 100, you'd have a maximum flash range of around 16.4 feet (92 / 5.6). Each time you double the ISO speed, flash range increases by 1.4x. So, at ISO 400 (which will increase noise), you'd have a maximum range of around 32 feet.

That's assuming a direct flash. If you bounce a flash for more even lighting, you'll lose a lot of flash range.

If you don't zoom in much, you'll have a lot more range (since the camera can use a wider aperture, represented by a smaller f/stop number).

You can also find brackets with a digital aware optical trigger built in. Here's one example:

Then, you could find a more powerful non-dedicated flash to mount in it's hotshoe, letting the optical slave built into the bracket trigger it.

But, you'd need to experiment with camera and flash settings for correct exposure with these types of slave setups (since a slave flash arrangement is not aware of your camera settings and just knows to fire when it sees a camera's built in flash fire).